Question

GASES The volume V of a gas varies inversely as its pressure P. If V=80 cubic centimeters when P = 2000 millimeters of mercury, find V when P=320 millimeters of mercury.

A. 500cm3
B. 12.8cm3
C. 8000cm3
D. 80cm3

Answer 1

A. 500 cm3

Explanation:

The general inverse variation equation is

y = k/x, where y varies inverse as x and k is the constant of proportionality.

Thus, if we substitute V for y and P for x in the equation, we have

V = k / x

To find k, we can plug in 80 for V and 2000 for P and solve for k:

80 = k / 2000

160000 = k

Finally, to find V when P = 320 millimeters, we can plug in 160000 for k and 320 for P and solve for V:

V = 160000 / 320

V = 500 cm3